In attempting to maintain a generally constant and comfortable temperature level in rooms, particularly large rooms, one major problem which is encountered is the significant variation between the temperature of the air near the ceiling and the air near the floor which results from the well-known principal that warmer air will rise. While the proper placement of heating and air conditioning ducts tend to alleviate this problem, even proper ductwork design does not solve the problem entirely, and the problem manifests itself particularly in large areas such as offices and commercial establishments.
It is apparent that such stratified temperature conditions may tend to create an uncomfortable environment for occupants of the space, and, more importantly perhaps, valuable energy is wasted in an attempt to maintain the lower portion of the room at a temperature level that is not uncomfortable for occupants. For example, when heating a large space, the hottest air will rise to the ceiling, leaving cooler air in the lower portion of the space where the occupants are, and it is therefore necessary to increase the amount of heated air which is dicharged into the room to maintain the lower portion at a comfortable temperature level.
Efforts have been made to deal with this problem by utilizing air moving devices located in the space to move the stratified air upwardly and downwardly to thereby mix the warmer and cooler air and obtain greater temperatures equalization. Familiar examples of such air moving devices are ceiling fans and air blowers mounted in spaced relation to the ceiling of the space to create downwardly directed air currents. However, many of these devices are quite inefficient and/or expensive because they do not effectively and efficiently convert the generally centrifugal air flow generated by a rotating impeller to an axial air flow that can be directed downwardly in a vertical direction to obtain the maximum efficiency for the device in equalizing the temperature of the stratified air. For example, ceiling fans are very inefficient because there is virtually no structure to properly channel the generally centrifugal air currents generated by the fan, and known ceiling mounted blowers, while they generally include some type of vanes for directing the air downwardly, utitilize such vanes in an inefficient manner which requires the use of a larger motor and a larger impeller to get the desired amount of air flow exiting downwardly from the blower. This inefficiency therefore increases the initial costs of the devices, and, because the devices are generally operated continuously, also increases significantly the energy consumption and operating costs of the devices.
In accordance with the present invention, a blower of the aforesaid type is provided with a unique air directing vane arrangement which is quite efficient and which creates an air flow that, upon leaving the blower, is directed downwardly in an essentially vertical flow path that provides excellent results in moving the air from the ceiling area to the lower portion of a room.